The invention relates generally to four-stroke internal combustion engines and to lubrication systems therefore. More particularly, the invention also relates to such four-stroke engines which included a crankshaft which, in the past, were supported by so called anti-friction bearings and which were supplied oil for lubrication by mechanical oil pumping arrangements.
As is well known, in many four-stroke engine installations, the lubricating oil is either pumped or splashed (or both) to the parts requiring lubrication. In these systems, engine debris and moisture can accumulate in the crankcase or oil reservoir. Consequently, in these engines, the lubricating oil is periodically drained and replaced to prevent build up or accumulation of engine debris and moisture which can be deleterious to proper lubrication and which may serve to contaminate the lubricating oil.
Attention is directed to the following U.S. Patents.
______________________________________ U.S. Pat. No. Inventor(s) Issue Date ______________________________________ 4,417,561 Seishi Yasuhara November 29, 1983 4,421,078 Erwin E. Hurner December 20, 1983 4,674,456 Timothy K. Merritt June 23, 1987 4,869,346 Donald M. Nelson September 26, 1989 ______________________________________
Attention is also directed to Japanese Application No. 3-206473 Filed Jul. 23, 1991.